(1) Field of the Invention
This invention relates in general to a mounting bracket, and more particularly to a mounting bracket for a sensor used to detect an object in the path of a closing overhead door.
(2) Description of Related Art
There are many types of mechanical door openers which are used to open and close overhead doors. In addition, there is legislation that requires all newly installed electronic garage door openers to have a safety device that will reverse the travel direction of a closing door if an obstruction is present within six inches of the door's closed position (ground level).
One type of prior art garage door safety device is a safety edge or compressible detector that is placed on the leading edge of the door. The advantage of this type of safety device is that the detector is located directly below the leading edge of the door. The detector travels with the door, and the detector senses objects in the path of the door throughout the entire travel path of the door. This type of safety device has the disadvantage that the door must physically contact an object before the door's downward motion is stopped.
U.S. Pat. No. 4,922,168, issued to Waggamon, et al., shows a safety system that uses a transmitter and a receiver which are laterally opposed near the edges of the door opening. The transmitter and the receiver mount a few inches away from the travel path of the door, and about four to six inches above the ground; and therefore, the transmitter and the receiver do not travel with the door as the door opens or closes. A beam is sent from the transmitter to the receiver. If the door is closing and an object is in the path of the beam, the beam will not be received by the receiver, and the door will stop and the travel direction of the door will be reversed.
An object can be positioned in the path of the closing door, yet not break the beam transmitted between the transmitter and the receiver. An example of this type of arrangement is a car that is parked so that the trunk of the car is in the path of the door while the beam passes unobstructed beneath the car. The beam between the transmitter and the receiver would pass under the car and not be interrupted, resulting in the closing door hitting the car.
U.S. Pat. No. 5,233,185, issued to Whitaker, and U.S. Pat. No. 5,596,840, issued to Teich, both show garage door safety systems which utilize sensors which travel with the garage door. The transmitting sensor and the receiving sensor are mounted adjacent to the door on support mechanisms which allow the sensors to vertically retract and extend. When the door is open, the sensors extend to a position adjacent to and below the leading edge of the door. As the sensors approach the ground, the lowest end of the support mechanism contacts the ground. As the door continues to close, the sensors vertically retract into the support mechanism until the door is fully closed. When the door opens, the sensors are again extended below and adjacent to the leading edge of the door.
To use these types of overhead door safety sensor mounts, an additional support mechanism must be attached to the overhead door. Obtaining proper positioning of the transmitter and receiver can be difficult, especially if the floor beneath the overhead door is not level. Additionally, the safety sensors are located adjacent to the leading edge of the door, not beneath the leading edge of the door.